Method of and apparatus for drying carbon tissues



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April 6, 1937. G. A. mass 2, 76,367

METHOD OF AND APPARATUS FOR DRYING CARBON TISSUES I Filed April 29, 1935 2 Sheets-Sheet 1 i fijfifiiiiii INVENTOL WM a. I ,BY 5

ATTORNEYS.

April 3 G. A. FRIESS 2,076,367

METHOD OF AND APPARATUS FOR DRYING CARBON TISSUES Filed April 29/1935 7 2 Sheets-Sheet 2 12 R R F F INVENTOR.

ATTORNEYS.

Patented Apr. 6, 1937 METHOD or AND arraaarus Foa name cannon rrssuss Gustave A. Friess, Rye, N. Y., assignor to News Syndicate Co. Inc., New York, N. Y., a corporation of New York ApplicationApril 29, 1935, Serial No. 18,759

My invention relates to a new and improved method of and apparatus for drying carbon tissues.

One of the objects of my invention is to pro- 5 vide an apparatus and method for shortening the drying period.

Another object of my invention is to provide a method and apparatus for drying the tissue, so as to prevent any buckling or curling of the 10 tissue, so that the dried tissue is in flat and planar form. I

Another object of my invention is to provide.

an apparatus which shall be simple and cheap to construct and operate.

15 Other objects of my invention will be set forth in the following description and drawings which-illustrate a preferred embodiment thereof, it being understood that the above statements of the objects of my invention is intended 20 to generally explain the same without limiting it in any manner.

Fig. 1 is a front elevation of a form of apparatus which may be used for carrying out said method. 25 Fig. 2 is a side elevation of Fig. 1.

Fig. 3 is a top plan-view of Fig. 1. Fig. 4 is a sectional view on the line 4-4 of Fig. 1. Fig. 5 is a sectional view on the line 5-5 of 30 Fig. 1.

Fig. 6 is a sectional view on the line. 6-6 of Fig. 1. V Fig. '7 is a sectional view on the line 1-1 of Fig. 4. l

5 Figs. 8 is a sectionalview on the line 8-8 of Figs. 9 --is a sectional view on the line 9-9 of Fig.

In printing photographs by means of the 4 photogravure or rotogravure method, it is necessaryv to prepare and to dry carbon tissues. These tissues are made of paper, having a gelatin coating on one side of the paper.

Heretofore such tissues have been dried by 45 placing them on sheets made of special absorbent felt and such sheets of felt, in contact with the tissues, were hung in a cabinet, so as to permit the felt to absorb the moisture of the carbon tissue. This process was lengthy and it 50 took about 1 to 2 hours in order to secure satisfactory drying.

In the improved apparatus shown,- a motor I operates a fan (not shown), which is located in a suitable fan-casing 2. The fan-casing 2 55 is connected by means of a pipe 3, to an inlet casing 4. Said inlet casing 4 has a mouth 5. The inlet casing 4 is provided with a suitable heater, which may be of the electric type.

In the embodiment described, the inlet cas- .ing 4 is provided with electrically heated elements 6. Each element 8 may be of conventional form, comprising a member in which a heating wire is imbedded. The outer shells of the elements 6 may be made of metal, and said outer shells may be insulated from the wall of 10 the inlet casing 4, by any suitable insulating means.

The heating wires of the respective heating elements 8, have their ends connected in parallel to a supply circuit which has the wires I and 8.

The inlet end of the 'pipe 3 is controlled in any suitable manner, as for example, by means of louvre blades 9, which may be adjusted if desired, so as to increase or decrease .the effective cross section of the inlet end of the pipe 3. 'Air is thus drawn into the fan-casing 2, and said air may be heated to any suitable temperature. The current supply to theelectric heater may be regulated, so as to regulate the temperature of the heated air. The air is then forced in the direction of the arrow shown in Fig. 1, into and down the casing In.

As shown in Fig. 4, the tissues T are placed upon the planarsurfaces of supports ll. Said supports II are preferably imperforate. They may be made of any suitable material which will not warp or bend under the effect of the heat or moisture.

The supports II are surfaces of shelves l2.

Referring to Fig. 6, it can be seen that each shelf I2 has a lateral U-shaped cross section. Each shelf l2 also has a downward flange I 2b at the left-hand end thereof, referring to Fig. 1 and Fig. 6, and it has an upward flange l2a at the right-hand end thereof, referring to Fig. 7.

The underside of each shelf I2 is provided with suitable perforated. means. Said perforated means are spaced from the underside of the shelf 12. Hence, and as shown more particularly in Fig. 7, a space S is formed between the underside of each shelf l2 and said perforated means. ,As shown in Fig. 7, said spaces communicate with the housing It. Baflies II are provided so as to deflect some of the air which passes downwardly through the casing I ll, into said chambers or spaces S. Henceeach sheet 01 tissue T has its paper face exnnsad tn placed upon the-upper 35 the downwardly directed .air currents which issue from the adjacent ripper space S. The

paper side of each sheet T is thus dried directly by means of a forced draft of heated air, while 5 the underside or gelatin face of the tissue T is in contact with a support made of non-absorbent and rigid and planar material. This material may be a phenol formaldehyde condensation resin, of the type known as Bakelite, or any suitable non-metallic or metal material. It can also be made of metal, having a lacquered surface, Said support could be made of absorbent material.

The perforated means at the underside of each shelf I2 may be of any suitable construction, as the only purpose of said perforated means is to downwardly distribute the current of hot air which is forced out of each chamber S.

The size and number of the holes in said perforated means can be regulated according to the velocity of the air current.

I have shown a particular embodiment of said perforated means, but I do not wish to be limited to the specific construction thereof.

Referring to Fig. 5, this shows perforated plates I4 and Ila having downward flanges at their adjacent edges, and such downward flanges are connected by means of a bar Ill, shown in Fig. 9, which has a U-shaped cross section. Said bar I6 plates I4 and I la by any suitable fastening means.

The perforated plate Il has imperforate bars II and IIa removably connected thereto, by means of screws I8 or other suitable fastening means.

The purpose of the bars I1 and IIa is to control the size and location of the perforated area of the plate I4. Said bars I1 and I'Ia could be i of any desired shape and area. Likewise, the perforated plate Ila has an imperforate bar I9 con- 40 nected thereto by screws or other fastening means. Hence the perforated areas of the plates Il and Ila are separated from each other and from the edges of the shelf I2, save that the-lefthand edge of the perforated plate Il, and the right-hand edge of the perforated plate Ila, substantially abut the corresponding edges of the shelf I2.

The perforated plates I4 and Ila have flanges which are connected to the front and rear flanges I21; and I2c of the shelf I2, and to the downwardly directed left-hand flange of the shelf I2. This is done by means of bars B, and bolts R, which have nuts connected-thereto.

The right-hand and downwardly directed flange of the member Ila, referring to Figs. 6 and '1, is connected to an extension of the adjacent wall of the. housing Ill. This extension also has a downwardly directed flange.

Referring to Fig. 5, the right-hand edge of the central branch of the plate I9 is turned downwardly, as indicated at I9a in Figs. 1 and'5. The left-hand ends of the pockets or spaces S are closed by means of a plate 3 0 which is suitably connected to the frame F of the apparatus. The

apparatus is mountedupon wheels W and it is provided with diagonal cross braces 3| as shown in Fig. 1.. Additional cross braces 3| are provided, as shown for example inFig. 4.

While the invention is particularly useful for drying carbon tissues, it may also be used for drying films made of celluloid or the like.

The ordinary carbon print is made on heavy paper, which carries a film of gelatin having carbon pigment.

This gelatin film is ordinarily in direct contact is connected to the flanges of the perforatedwith the support II. It would not be departing from the invention if a sheet of felt or the like were placed upon the shelf I2 and the carbon tissueor print was located upon said porous member.

Any suitable additional means may be used for preventing leakage of the heated air which is forced into each chamber S, save in a downward direction.

It would not be departing from the invention if the carbon tissues were held in some plane other than the horizontal plane.

Generally speaking, a current or currents of heated air are directed against the exposed faces of the carbon tissues and in a direction substantially perpendicular to said exposed faces.

The heated air strikes each said exposed face, and the air then spreads laterally over said exposed face. The pressure of the heated air against the exposed face of the carbon tissue, may be suflicient to prevent any curling or wrinkling thereof, during the drying process. However, said pressure is ordinarily very slight, since air can escape readily through the front and rear of the apparatus.

' Since the gelatin face of the moist carbon tissue is in close and adhering contact with the support I I, which is preferably rigid and imperforate, the carbon tissue is dried uniformly so as to prevent any curling or wrinkling.

Referring to Fig. 8, this shows how a plate G serves to prevent any leakage of the hot air from the chamber S. v

The sizes of the plates I1, I'Ia and I9 may be varied, and said plates can be adjusted, since they are removably connected to the perforated plates. 1 have discovered that if the hot air is uniformly applied to the carbon tissue, the drying is uneven, because the edges of the tissue dry before the inner part of the tissue. Hence the edges dry and shrink before the central part of the tissue has dried. This uneven drying and shrinking makes it diflicult or impossible to secure registration accurately, especially in multi-color rotogravure work.

The use of the imperforate plates I'I, I'Ia and I9, in combination with the baffles I9a, (which are important) distribute the air so as to secure uniform drying, thus preventing curling or wrinkling or uneven shrinking of the tissue.

Said plates I1, I'Iw and I9 prevent the downward currents of air from directly impinging upon at least two edges of the tissue, and upon a portion of the tissue intermediate the edges of the tissue. The bames I9a laterally deflect the air which passes through the perforations of plate Ila, which are directly adjacent the central leg of plate I9. Hence some of the air moves in a direction which has a component which is parallel to the face of the tissue. The area of the carbon tissue may be the same as the combined areas of plates Il and Ila including those parts of said plates Il and Ila, which are covered by imperforate plates I1, I'Ia and I9. Said'carbon tissue is located directly below said plates I4 and Ila. Said carbon tissue may be of less area or of greater area than said combined area of plates Il and Ila. The air currents may be disposedso as to avoid any direct impingement thereof upon any of the edges of the tissue.

The baffles I9a cause a lateral movement of the heated air, that is,a movement in a direction which has a component parallel to the upper paper face of the planar sheet of tissue. Said lateral current of hot air may be supplemented in a direction parallel'to the face of the carbon tissue, in which case the componentis one hundred per cent of the direction of movement of the air.

If the sheet of carbon tissue is located upon a substantially non-porous support, the paper base of the sheet is exposed directly to the action of heated air or other heated gas or vapor, and the gelatin film or coating is substantially protected from exposure to said heated air or gas or vapor.

If the sheet of carbon tissue is rectangular so that its length is greater than its width, the plates l1 and "a and I 9 are located adjacent the long edges of said sheet of carbon tissue, so that the long edges are subjected to less direct heat than the interior of the sheet of carbon tissue. Under such circumstances and even if apart of the shorter edge portions of said rectangular sheet is directly exposed to the heated air, the sheet will not curl during the drying thereof. The paper which is in common use for preparing carbon tissue has a grain or direction of fibre, which isparallel to the length of the paper. Hence, by protecting the longitudinal edges of the paper, the curling of the paper is substantially prevented.

For convenience the perforated plates l4 and Ma may be regarded as constituting two separated sources of heated air, since the lateral leg of the plate l9 prevents the downward movement of the air adjacent said lateral leg.

I have shown preferred embodiments of my invention, but it is clear that numerous changes and omissions can be made without departing from its spirit.

3 I claim:

1. A method of drying carbon tissue which "consists in supporting a sheet of wet carbon tissue upon a substantially rigid support, and directing a current of heated air against the exposed face of said carbon tissue, while preventing contact between said air current and a suflicient edge portion of said tissue, so as to cause said tissue to dry and shrink substantially uniformly.

2. A method of drying a sheet 01' carbon tissue having a paper base and a gelatin coating at one side of said paper base, which consists in subjecting said sheet to the action of a drying medium, while preventing contact between said drying medium and sumcient of the edge portion of said sheet, so as to cause the tissue to dry and shrink substantially uniformly.

3. A method of drying a substantially rectangular sheet of carbon tissue which consists in causing air to impinge directly upon the exposed paper face of said carbon tissue, while substantially preventing contact between two of the edges of said sheet of tissue and the said tissue to dry and shrink out curling.

4. A method of drying a substantially rectangular sheet of carbon tissue which consists in caus ing air to impinge directly upon the exposed paper face of said carbon tissue, while substantially protecting two of the edges of said sheet of tissue from the air, and also preventing said air from impinging directly upon sheet of tissue which of said sheet.

substantially withis intermediate the edges GUSTAVE A. FRIESS.

air, so as to cause a lateral zone of the 

